A water toilet, which is generally installed in a bathroom or a rest room, is equipped with a toilet body on which a user can sit to relieve him/herself. A water tank is provided behind the toilet body, and contains therein washing water, which drains excrement from the toilet body into a water-purifier tank.
In addition, a water supply apparatus, which supplies washing water into the water tank, is disclosed in Korean Registered Utility Model No. 138379, entitled “Apparatus for Supplying Water for Water Tank in Water Toilet,” previously filed by the applicant as Application No. 20-1996-0010735.
This registered utility model has the problem of not supplying enough washing water when the washing water has low pressure, since washing water supplied from a hydrant fills up a water tank from bottom to top.
When the level of the washing water contained in the water tank reaches a high water mark, the packing of a float closes an opening/closing hole. As the float rotates and is displaced upwards depending on the level of water and the interval between the packing of the float and the hole for opening and closing becomes narrower, washing water supplied to the hole for opening and closing creates a noise.
In order to solve such a problem, a Korean Patent No. 758827, entitled “Apparatus for Controlling Supply of Water in Water Toilet,” was subsequently filed by the applicant as Application No. 10-2005-0124932.
This patent has an advantage in that a fill valve is mounted to the upper end of an overflow pipe to supply washing water to a water tank from top to bottom in order to solve the foregoing problem. However, when the supply of washing water is stopped or suspended, washing water, which is contained in the water tank or in a toilet body, may instantaneously flow back through the fill valve toward a hydrant because of the backflow pressure of washing water, thereby polluting the hydrant. In addition, when the supply of washing water is resumed, it may become unsanitary since water is supplied through the polluted hydrant to a wash basin, a shower, or a kitchen valve.